Stay-bolt-testing device.



E. l. DODDS.

STAY BOLT TESTING DEVICE. APPucATloN F|LED1ULY 25.1616,

'Patented Aug. 7, 1917.

t .A w i i? l\\\\\\\\\\\\\\Jv WJTNESSES UNITED sTATEs PATENT oEErcE.

l 'ETHAN I. DODDS, 0F PITTSBURGH, PENNSYLVANIA, ASSIG-NOR TO FLANNERY BOLTl COMPANY, 0F PITTSBURGH,` PENNSYLVANIA..

STAY-BoLT-TESTING DEVICE.

specification of Letters Patent. Patented Aug, 7,1911

application mea' July 25, 191e. serial No. 111,39.

To all whom t may-concern:

Be it lmown that I ETHAN I. DoDDs, a citizen of the United tates, and a resident of Pittsburgh, in the county of Allegheny and State lof Pennsylvania, haveinvented certain new and useful Improvements in.

.y Same.

. This" invention relates to improvements in means for testing stay bolts of boilers,- one object of the invention being to provide simple and efficient electromagnetic means which will 'operate promptly to detect a broken bolt.

f A further object is to so construct a magnetic bolt testing device that readily handled and manipulated and which shall be positive and certain in action.

'With these and other objects in view the invention consists in certain novel features of construction and combinations of parts as hereinafter set forth and the claims.

In the accompanying drawings; Figure 1 is a view in elevation of a bolt tester showing -an application of my improvements; Fig. 2 is a vertical sectional view, and Fig. 3 is a plan view. v

Inlthe application of stay bolts to boilers, it is customary to attach one end of the bolt 1 to th'e inner boiler sheet 2 and to provide the other end of the bolt withl a spherical or partly spherical head 3 having a bearing 1n a 'sleeve l passing through the outer sheet' l5 of the structure. This sleeve is externally c threaded to facilitate its attachment to the sheet 5 and also to receive a cap 6 which incloses 'the head of the bolt; the structure of the assembled parts being such as to leave a clearance 7 between the head of the bolt and the inner face of the cap. Should the bolt break'at any point, the head thereof will become loose within the cap 6 and may 1 move therein through the clearance space the head of a broken stay bolt to forcibly engagekthe cap and by the sound or vibration: produced by the striking of the bolt 7 and engage the inner face of said cap. My improved `detector is designed to cause `head againstthe' cap, denote the fact that the bolt is broken. vvShould no sound or vit may bel pointed out in vibration occur when the detector is applied, this fact will denote the integrity of the bolt.

The improved testing device or detector comprises a magnet fraine or shell 8, the head 9 of which is formed with a central enlargement 10 which forms a seat for the upper end of a laminated core 11 secured in place as hereinafter explained. The lower end of themagnet frame or shell is closed' bya non-magnetic plate- 12 and the latter is made with a central opening 13 through which the free end of the magnet core 11 passes. For convenience of manufacture, thelaminated core 11' may be made angular in cross section and its free projecting end is made with a recess 14 to engage over and conform to the contour of the cap 6 of the stay bolt structure.

A hollow handle 15, which may be made of aluminum, is mounted upon the head 9 of the magnet shellk and the base 16 of said handle may be formed with a flange 17 to rest on said head so as to provide a ventilating space 18. The base 16 of the handle may be secured to the head 9 by means of screws 19 and also by means'of a large central screw 20, the latter passing freely through a hole'21 in the head of the magnet frame and entering the upper end of the magnet core 11 so as to secure the latter firmly to its seat. On leg, 22, of the handle may be made solid and integral with the base plate 16, while the other leg 28 is made tubular and may also be integral with the hase plate. Thus the entire handle st ructure may be made or cast in a single plece.

The coil 24 of the magnet occupies the annular space within the frame or shell 8 and around the core 11, and the terminals of this coil pass through a hole 25 in the head 9 of the magnet frame and enter the tubular handle. One end of the handle is open for the passage of the leading-in wires of the magnet coil and the bore of the tubular handle is preferably contracted somewhat at its open end as indicated at 26 for the reception ofa flexible coil 27 which serves to protect the leading-in wires 28,-said ieXible coil being secured in place by means of a screw 29 or a plurality of such screws.

A suitable switch 80 will be suitably placedlin the circuit of the magnet coil, and may be located on the handle portion of the structure.

ics

When the recessedend of the magnet core y is applied to a cap6 of the stay bolt structure, the closing of the circuit of the magnet coil will result in the generation of magnetic lines of force which will pass through,

the cap will cause a sharp sound or jar which will indicate to the operator that the bolt is broken,-viz., that the parts thereof have become severed.

Should the bolt break in proximity to the inner sheet, 2, it would be liable to drop to an inclined position andl the head might bind in its bearing in the sleeve 4 due possibly to a collection of incrustation which might enter by reason of the loosened bearing of the head of the broken bolt. Under such conditions, a magnet structure such as above described may be applied to the inner head of the broken bolt so as to cause the body of the depending broken bolt to be raised or moved suiliciently to insure the operation of the magnet structure applied to the cap to cause the head of the bolt to strike the cap as previously explained.

Having fully described my invention what I claim as new and desire to secure by Letters-Patent, is

1. A testing device forstay bolts in boiler structures, comprising a shell having a head at one end, a non-magnetic plate secured rto the other end of said shelland having a hole therein, a core secured to the head of the shell and passing through the hole in said non-magnetic plate, the free end of said core having a recess to conform lap,- proxirnately to the contour of the cap of a staybolt structure, a coil Within said shell encircling the core, and a handle secured to the head of said shell. l

2. A testing device for staybolts in boiler structures, comprising a shell having a head at one end provided With a central hole, a

'plate secured to the'other end of said shell and having a central Vhole, a core extending through the shell and through the hole inl ing Witnesses.

ETI-IAN I. DODDS.

Witnesses:

F. H. ALLIsoN, EDWIN SPENCER RYCE. 

